#include <stdio.h>

int main()
{
    char killer = 0;
    for (killer = 'a'; killer <= 'd'; killer++)
    {
        if((killer != 'a') + (killer == 'c') +(killer == 'd') + (killer != 'd') == 3)
        {
            printf("凶手是：%c",killer);
        }
    }
    return 0;
}